I have somethings to say:
To DMK, I can understand wanting a fish, but you have to buy them to suit your tank, not to suit your future tank. You could never know how long it will take for you to get a larger tank setup, meanwhile the fish you have quickly outgrow your current tank, and begin to harm themselves and the other fish living in the tank. Honestly, you are super fortunate, and you are throwing that fortune down the drain. You are getting beautiful fish, left and right, and you aren't providing for them, nor are you thinking about their future needs. So I ask that you please stop buying fish. If anything, ask about them first. You are less likely to end up with a giant, expensive mess if you listen to the advice of those who have been in this hobby longer than you. As it stands, your tank is far to overcrowded. You need to figure out what you are going to do with the fish you have, before you should figure out which fish you want next. Buying the stingray was a mistake, I'm sure you can fix that mistake by taking it back. After you handle the stingray, I want you to put all of your effort into getting the larger setup built. Once it is cycled and your fish are in a better home, then, and only then, can you even start thinking about buying a new fish.
To everyone else, I see your frustration, and I feel it with you. I believe DMK is still too young to be in high school. We need to act like surrogate parents to him. We need to teach him the skills of our hobby. Decision making is a skill. And I think it will be far more easier to attempt to teach him the reasoning behind our advice, than to try to drill the advice in. I understand that you all have tried to reason, but when that reason is mixed in with pointless arguments about whether all this is just a large troll, or whether this kid is telling the truth, is not going to make him want to listen to us. I feel that from now on, if you don't anything productive to say to him, don't say it at all. So that those who do want to help, can do so without others taking the focus.
That is pretty much all I have to say. I apologize if my thought process is discombobulated. But it is just my $.02.